The girls, who are over in Sin City to film two hour-long episodes, bumped into Rita while partying at celeb hotspot Hakkasan on Friday night (27 September).
Abi and Jasmin watched Rita's boyfriend, DJ Calvin Harris, play the decks and later joined Rita in the DJ booth where they posed for photos.
The girls weren't quite starstruck though, as Jasmin knows Rita from stage school, so it was more of a long overdue reunion!
Posting a snap of the pair to Instagram, Jasmin said: "@ritaora #hakkasan such a good night! Aww reunited from stage school catch up again soon girl xx."
Rita, who partied in Vegas with her sister Elena and model Kate Upton, looked stunning in a red lace dress.
The 22-year-old tweeted that she was making a "quick Vegas stop" before returning to London to sing at a charity concert last night.
Abi and Jasmin have been hitting every club on the Vegas Strip since arriving, so it's no surprise that they bumped into someone famous!
Check out more of the TOWIE stars in Vegas below:
Copyright: Instagram joeyessex90